Powdery/granular material flowability is evaluated, for example, by measuring an angle of repose, a degree of compaction or a degree of aggregation. For example, an index value used to evaluate flowability is calculated by the Carr method and evaluated.
A method for measuring an angle of repose, which method is utilized upon evaluating such flowability, is disclosed, for example, in patent literature 1. This patent literature 1 discloses a method for measuring an angle of repose of a wet powdery/granular material using an apparatus including, from the top, a mesh screen, vibrating means for vibrating the mesh screen, a powdery/granular material sample pouring funnel, a table used to measure the angle of repose, and a support for supporting the vibrating means and the sample pouring funnel and particularly a method for measuring an angle of repose of a wet powdery/granular material, wherein the liquid content of the powdery/granular material sample lies within a range of 10 to 60 weight %, the mesh size of the screen mesh is 710 to 5600 μm, and the diameter of the bottom orifice of the sample pouring funnel lies within a range of 5 to 15 mm.
Further, the Japanese Industrial Standards JIS Z 2502 (2000) or ISO 4490 specifies a “Metallic Powdery/Granular Material—Flowability Testing Method”. This “Metallic Powdery/Granular Material—Flowability Testing Method” is roughly a method for measuring a time required for 50 g of a metallic powdery/granular material to flow through an orifice of a calibrated funnel (Hall flowmeter) of a standard size by means of a stop watch and measuring the flowability of the metallic powdery/granular material based on this time.
The evaluation method according to the background art is for evaluating the flowability of the powdery/granular material from the angle of repose, degree of compaction and degree of aggregation that are measured in a stationary state of the powdery/granular material, but not for measuring the flowability of the powdery/granular material in a dynamic state of the powdery/granular material. Thus, evaluations by the evaluation method according to the background art could not be said to precisely reflect the flowability of the powdery/granular material in some cases.
Further, since a test is conducted as described above according to the “Metallic Powdery/Granular Material—Flowability Testing Method”, there is an inconvenience that the powdery/granular material to be measured is limited to a metallic powdery/granular material naturally discharged by the action of gravity. The above “Metallic Powdery/Granular Material—Flowability Testing Method” cannot be applied, particularly, to adhesive powdery/granular materials.
[Patent Literature 1]
Japanese Unexamined Patent Publication No. 2002-162329